All Questions
Tagged with positrons or antimatter
988 questions
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Antimatter + Matter in a box [closed]
Absolute beginner to physics here, please no judgement, just trying to get my head around some concepts. Hypothetically, lets say I have an indestructible box, and in that box I have 1g of matter, and ...
- 13
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0
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69
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Do a particle and an anti-particle have to be of opposite colors to annihilate? [duplicate]
Could you tell me which of these three is closest to the truth?
A green up quark will annihilate any anti-quark.
A green up quark will only annihilate an anti-green anti-quark.
Color charge shifts ...
- 101
20
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3
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What happened to all of the energy created at the Big Bang when the matter and antimatter annihilated each other?
Supposedly, at the moment of 'Creation', only a billion-and-one or a-billion-plus-two matter particles were created for every billion antimatter particles. Then, the vast majority of both proceeded ...
- 5,035
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1
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588
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Negative energy in special relativity
I am currently studying Quarks and Leptons by Halzen&Martin, and I have come across the typical presentation of the negative energy problem in QFT, introducing the free particle field in the Klein-...
- 2,646
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Why didn't the universe immediately annihilate after the Big Bang? [duplicate]
If the Big Bang created matter and antimatter in equal amounts, how come the entire universe didn't just annihilate into nothingness? Why is there more matter and only a little bit of antimatter?
- 79
5
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What would be different in antimatter fusion chains?
Antimatter behaves identically in regards to the electromagnetic and strong nuclear force, so many fusion reactions clearly would have exact antimatter counterparts. For example, antideuterium + ...
- 36.2k
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138
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What would happen if we tried to replace the electrons captured inside octafluorocubane with antiprotons?
The most critical question is: Is it stable? If it is unstable, how long will it last?
- 197
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156
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Can the distribution difference of particles and antiparticles be used to distinguish them?
Consider the distribution
$$n_\epsilon=\frac{1}{\exp[(\epsilon-\mu)/T]+1}$$
If particles and antiparticles have opposite $\mu$, that is $\mu_+=-\mu_-$, the number distribution of particles and ...
- 513
2
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0
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144
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Can a massive fermion be its own antiparticle?
I am currently reading Quarks and Leptons by Martin and Halzen, more precisely the chapter on the Dirac equation and its solutions. When attempting to solve the eigenvalue problem for the Dirac ...
- 2,646
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131
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Entropy Reduction in Radioactivity using Antimatter
For this scenario, I will be using this equation:
$$\tag1{}^{10}_{\ \ 5}\text B+{}^1_0n\rightarrow{}_3^7\text{Li}+{}_2^4\text{He}+dQ$$
where $Q$ is the energy that was converted from mass, some ...
- 19
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2
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354
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Effect of particle charge on scattering amplitude
In QED, consider for example the scattering process $e^-\mu^- \to e^-\mu^-$, with the leading order Feynman diagram
(time flows from bottom to top).
The scattering amplitude is, using standard ...
- 472
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112
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Reference request: Energy-momentum tensor for antimatter in general relativity
The intended setting is non-quantum general relativity.
My question: What is the relation between the energy-momentum tensor $T^{\mu\nu}$ and the baryon four-current $J^\mu$ in the case of antimatter, ...
0
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0
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107
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The $\bar{5}$-representation of the $SU(5)$ model of Grand Unification
First of all I am aware that the $SU(5)$ model of the Grand Unification is already outdated, but it does not really matter for my question.
When the basic representations of the $SU(5)$ model are ...
- 10.5k
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172
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How do the directions of internal lines in Feynman diagrams relate to energy and momentum transfer?
I'm trying to gain an intuition for drawing Feynman diagrams. I'm quite confused by the direction of the internal lines / propagators though. Am I right in the following understanding? If I put the $x$...
- 1
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144
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Does antiparticles with different spin annihilate?
A particle and antiparticle pair annihilate converting their mass to pure energy (eg- electron positron annihilation) if they both have different spins their spin before and after annihilation is zero ...
- 613